Mechanical drive



June 21, 19380 7 H. PFANNENSTIEHL.

MECHANICAL DRIVE Filed April 20, 1934 IN V E N TOP H. P54 NENST/EHLATTORNEY Patented June 21, 1938 UNITED STATES PATENT OFFICE MECHANICALDRIVE York Application April 20, 1934, Serial No. 721,505

12 Claims.

The present invention relates to a mechanical drive and moreparticularly to means for driving a flexible member.

An object of the invention is to eifect longitudinal movement of astraight flexible member by means connected intermediate the length ofthe memberwithout causing it to buckle or bend.

Another object is to control the flexible member from the intermediatelyconnected driving means in such manner that both end portions are undertension.

The invention will be hereinafter described as applied to an extremelyflexible opaque curtain constituting an element of the receiving orrecording apparatus of a picture transmission system adapted for use inan illuminated room or compartment.

One form of picture receiving or recording apparatus to which theinvention may be applied comprises a rotatably driven cylinder having alight sensitive film mounted thereon, the film loaded cylinder beingenclosed in a light-proof container provided with a longitudinallyslotted extension which engages a housing for a trackway in which aflexible curtain may be moved back and forth with respect to thecontainer, by a longitudinally driven optical system having a tubularextension which projects through a slot in the housing and through anopening in the curtain at a point intermediate its length, through whichextension and opening a spot of intense light of small dimension may bedirected to the light sensitive film carried by the cylinder. Thehousing for the trackway is provided with a longitudinal slot alignedwith the slot in the container and, at its respective ends, comprisescylindrical portions which respectively enclose rollers to which theends of the curtain are connected and on and off which respectivesections of the curtain may be wound and unwound, depending upon thedirection of movement of the optical system. Integral with therespective rollers or secured thereto are pulleys which are coupled by abelt or cord, the cord is applied to the pulleys in such manner thatwhen the optical system moves in either direction to apply tension toone section of the curtain, which for 50 convenience may be called thefollowing section, to unwind the curtain from one of the rollers, theother roller is rotated by the belt in such direction as to wind thereonthe section of the curtain preceding the optical system, i. e., theadvance section, whereby tension is applied to this section with theresult that such advance section does not tend to bend or buckle.

Preliminary to the recording operation a photographic film is mounted onthe cylinder which is inserted in the container in a dark room, the slotin the extension is closed by a shutter which excludes light therefromwhile the containeris being transferred from the dark room through theilluminated compartment to the apparatus. After the container has beenapplied to the apparatus with its slotted extension in engagement withthe trackway housing, and hence in position to have its slot sealed bythis housing and the movable curtain, the shutter is removed.

During the recording operation the intensity of thespot of lightsupplied by the optical system is controlled in accordance with thechanging values of the incoming picture current to provide a spot oflight of varying intensity, and, due to the relative motion of thecylinder and optical system, this varying light spot is caused to scanthe light sensitive surface in a succession of spiral traces, to producea record of the subject scanned at the transmitter.

A more detail description of the invention follows and is illustrated inthe attached drawing;

wherein Fig. 1 shows a view in elevation of a picture receiver havingthe invention applied thereto, with parts broken away; and

Fig. 2 illustrates a cross-section of the picture receiver with parts inelevation.

Referring to the drawing, there is shown a picture receiver comprising abase 13 for supporting the recording apparatus, including a motor Mconnected by a clutch, enclosed by the housing H, a container C whichencloses a cylinder having a light sensitive film mounted thereon; ahousing D which is provided with a trackway for the curtain and enclosesrollers on and off which the curtain may be wound and unwound and ahousing E enclosing an optical system.

The motor M is adapted to be coupled by a clutch i, diagrammaticallyindicated as an electromagnetically controlled unit, to a drive shaft4,"

2 which is directly connected to the cylinder 3, enclosed within thelight-proof container C, and through gearing 4 to a lead screw 5, whichdrives the optical system longitudinally of the apparatus and hencelongitudinally of the cylinder 3.

The optical system is designed to supply a spot light of the desiredconfiguration and of small dimensions which is focussed on the lightsensitive recording surface or film carried-by the cylinder 3. The lightspot is controlled by incoming picture current to vary in intensity inaccordance with the tone values of the successive elemental areas of thesubject scanned at the transmitter. By virtue of the rotation of thecylinder and the longitudinal movement of the optical system, which areeffected in synchronism and in phase with a similar scanning mechanismat the transmitter, the varying spot of light scans the light sensitivesurface in a succession of spiral traces to produce a record of thesubject scanned at the transmitter. The clutch may be of any suitabletype, such as, for example, of the designdisclosed in U. S. Patent2,105,897, of C. C. Towne, issued Jan. 18, 1938.

The optical system is not a feature of this invention and hence furtherdescription thereof appears to be unnecessary. However, the apparatus isto be used in a normally lighted room or compartment and hence provisionmust be made to permit the spot of light to illuminate successiveelemental areas of the light sensitive material carried by the cylinder3 and, at the same time, to exclude from the container light supplied bythe source illuminating the r-oom or compartment in which the apparatusis installed.

As shown in Fig. 2 the cylinder 3 is provided with a strip 6 for holdinga sheet of light sensitive material in intimate contact with itssurface. Any suitable means may be used to secure the light sensitivematerial to the cylinder. A satisfactory arrangement for this purpose isdisclosed in U. S. Patent 2,085,093 of M. C. Gauthier, issued June 29,1937. After the sheet has been secured to the cylinder in a dark room,it is enclosed in the light-proof container which is provided with alongitudinally extending slot 1. A flanged plate 8 is associated withthe slot and cooperates with the external surface of the container toprovide a guideway 9, into which a shutter may be inserted after thefilm loading operation has been completed and before the container isremoved from the dark room.

The slotted section of the container C is provided with an extension I0,comprising side and end walls secured in light-proof engagementtherewith and a face plate having a slot l2 in alignment with theslot 1. The upper end of plate II has an extended hook-shaped portion l3adapted to engage a flange l4 provided on the adjacent wall of thehousing D, and a depending flange l5 engaging a beading l6 also carriedby this housing. The container C is supported by depending legs F whichengage bearing blocks G carried by the base B. The housing D is providedwith U-shaped members adapted to provide a trackway for a slidingcurtain l8.

The optical system, enclosed by the housing E, is provided with atubular extension l9 which projects through a slot in housing D andthrough an opening in the curtain l8. This extension is provided with aflange 20 against which the curtain is seated and securely held by thenut 2|. This system is mounted on a base supported on rails 22, and thebase is provided with depending arms 23 which carry a nut 24 adapted tobe moved into and out of engagement with the lead screw 5 by a lever(not shown).

The ends of the housing D are provided with cylindrical casings 25, eachof which encloses a roller 26 having formed integrally therewith, orsecured thereto, a pulley 21, and the pulleys are enclosed by anextending portion 28 supported by the casings 25.

The respective ends of the curtain l8 are attached to the rollers 26,and a driving belt 30,

after passing over idler pulleys 3| included in the extension 28, hasits respective ends attached to the pulleys 27. This belt is providedintermediate its length with a spring 32, which serves to compensate anyvariations in the tension transmitted through it.

The apparatus is prepared for the recording operation in a dark room bysecuring a film on the cylinder 3 and inserting the shutter in place inthe slideway 9, the container C is attached to the apparatus installedin a lighted room or compartment with its slotted extension ID inengagement with the housing D, the shutter is removed, and the opticalsystem adjusted to the right hand end of the machine.

To effect recording, the motor is connected to the power source and theclutch actuated to connect it to the drive shaft 2, whereby the cylinderand lead screw are rotated and the optical system is driven by the leadscrew in a direction toward the left hand end of the machine, with theresult that the curtain moves toward the left and a tension is therebyapplied to the section of the curtain connecting the optical system withthe right hand roller 26, i. e., the following section of the curtain.This right hand roller and its associated pulley 21 are thereby causedto rotate in a counten-clockwise direction. The driving belt 30, afterpassing over the right hand idler 3|, is so wound on the right handpulley 21 that, as the curtain moves toward the left to rotate the righthand pulley 21 and its associated roller 28 in a counter-clockwisedirection, the belt moves toward the right and after passing over theleft hand idler 3|, is applied to the left hand pulley 21 in such mannerthat both it and the associated roller 26 are rotated in a counterclockwise direction; whereby the curtain is wound on this roller to apply atension to the section of the curtain connecting it to the opticalsystem, i. e., the section to the left of the optical system or theadvance section. When the recording operation is completed, the opticalsystem, which may either be at the left hand end of its path of travelor at some point to the left of the starting position, is disconnectedfrom the lead screw and may then be manually moved to any desiredposition. Assuming that the optical system is returned to the startingposition, the left hand section of the curtain, i. e., the sectionconnecting it with the left hand roller 26, or, in other words, thefollowing section, will be under tension and will thereby cause the lefthand roller 26 and its associated pulley 21 to rotate in a clockwisedirection, the driving belt will be wound on the left hand pulley andunwound from the right hand pulley which is thereby rotated in aclockwise direction as is also its associated roller; with the result,that the curtain is wound on the right hand roller and a tension isapplied to the portion of the curtain connecting it with the opticalsystem, i. e., the section to the right of the optical system which hasnow become the advance section. During these operations the spring 32serves to keep the belt and thereby the curtain l8 under constanttension.

The present invention, therefore, provides an arrangement in which astraight flexible member may be moved longitudinally in either directionby a driving force applied intermediate its length in such manner that,irrespective of the direction of the applied force and hence thedirection of movement of the member, a uniform tension is applied to thesections of the member on opposite sides of the point of application ofthe driving force.

What is claimed is:

1. A picture receiving apparatus comprising a light-proof casingenclosing a light sensitive film carried by a rotatable member andprovided with a longitudinally extending slot, a straight flexiblemember for continuously sealing said slot, supports for said member,means for connecting the respective ends of said member to saidsupports, means connected to said member intermediate its length formoving said member longitudinally of said slot, and means formaintaining under tension the sections of said member on oppositesidesiof said point of intermediate connection, said last-mentionedmeans comprising means, controlled by the means for efiectinglongitudinal movement of said member, for actuating said supports toapply tension to one of said sections.

2. A picture receiving apparatus comprising a light-proof casingenclosing a light sensitive film carried by a rotatable member andprovided with a longitudinally extending slot, a straight flexiblemember for continuously sealing said slot, supports for said member,means for connecting the respective ends of said member to saidsupports, means connected to said member intermediate its length formoving said member longitudinally of said slot, and means, controlled bythe means for eifecting longitudinal movement of said member andcoupling said supports, for causing the section of said member on oneside of said connecting point to apply a tension to the section of saidmember on the other side of said connecting point.

3. A picture receiving apparatus comprising a light-proof casingenclosing a light sensitive film carried by a rotatable member andprovided with a longitudinally extending slot, a straight flexiblemember for continuously sealing said slot, supports for said member,means for connecting the respective ends of said member to saidsupports, means connected intermediate the length of said member formoving it longitudinally of said slot and for thereby applying a tensionto one section thereof, and means for coupling said supports, saidcoupling means being controlled by the means for effecting longitudinalmovement of said member to apply tension to the other section of saidmember.

4. A picture receiving apparatus comprising a light-proof casingenclosing a light sensitive film carried by a rotatable member andprovided with a longitudinally extending slot, a straight flexiblemember for continuously sealing said slot, supports for said member,means for connecting the respective ends of said member to saidsupports, means connected intermediate the length of said member formoving it longitudinally of said slot in either direction, and means formaintaining the sections of said member between the intermediateconnecting point and the respective supports under uniform tension asthe member is moved in either direction, said means comprising meanscoupling said supports, and operable by movement of said member totransfer tension from one section to the other.

5. An electro-optical apparatus comprising a container enclosing arotatable light sensitive film and provided with a longitudinallyextending slot, a straight flexible member for sealing said slot,rollers on and off which sections of said member may be Wound andunwound, respectively, means connected intermediate the length of saidmember for unwinding one section from one of said rollers, and meanscontrolled by said unwinding operation for winding the other section ofsaid member on the other roller.

6. An electro-optical apparatus comprising a container enclosing arotatable light sensitive film and provided with a longitudinallyextending slot, a straight flexible member for sealing said slot,rollers to which the respective ends of said member are connected,optical means connected intermediate the length of said member to moveit longitudinally and thereby apply tension to one section of saidmember for unwinding said section from one of said rollers, and meanscontrolled by said tensioned section for rotating said other rollertoapply tension to the other section of said member.

7. An electro-optical apparatus comprising a container enclosing arotatable light sensitive fllm and provided with a longitudinallyextending slot, a straight flexible member for sealing said slot,rollers to which the respective ends of said member are connected,tensioning means for coupling said rollers, and means connectedintermediate the length of said member for moving it longitudinally toapply tension to one section of said member and thereby rotate saidrollers to actuate the tensioning means to apply tension to the othersection of said member.

8. A picture receiving apparatus comprising a light-proof containerenclosing a light sensitive film carried by a rotatable cylinder andprovided with a longitudinally extending slot, means for continuouslysealing said slot including a flexible member, an optical system havinga light outlet aligned with said slot, means for connecting said opticalsystem in an aperture intermediate the length of said member, means formoving said optical system and said member longitudinally of said slotto thereby cause tension to be applied to a section of said member onone side of said optical system, and auxiliary means for applying asimilar tension to the section of said member on the other side of saidoptical system, said auxiliary means being actuated by the movement ofsaid optical system.

9. A picture receiving apparatus comprising a light proof casingenclosing a light sensitive fllm carried by a rotatable member andprovided with a longitudinally extending slot, a straight flexiblemember for continuously sealing said slot, supports therefor havingsurfaces substantially in the plane of said member, means for securingthe respective ends of said member to said supports, means connected tosaid member at a point intermediate its length for moving itlongitudinally of the slot, and means associated with said supports formaintaining under tension the sections of said member on opposite sidesof said point of connection.

10. A picture receiving apparatus comprising a light proof containerenclosing a light sensitive film carried by a movable member andprovided with a longitudinally extending slot, a straight flexiblemember for continuously sealing said slot and having its respective endsconnected to rotatable supports, means for moving said memberlongitudinally of said slot, and means for permanently connecting saidmeans for effecting longitudinal movement at a point intermediate thelength of said sealing member.

11. A picture receiving apparatus comprising a light proof containerenclosing a light sensitive film carried by a movable member andprovided with a longitudinally extending slot, a straight flexiblemember for continuously sealing said slot ill) and having its respectiveends connected to rotatable supports, means for moving said memberlongitudinally of said slot, means for permanently connecting said meansfor effecting longitudinal movement at a point intermediate the lengthof said sealing member, and means for applying a force to at least oneof said rotatable supports to cause it to exert a pull upon saidflexible member in the direction of the push exerted thereon by saidmeans for longitudinally moving said member.

12. A picture receiving apparatus comprising a light proof containerenclosing a light sensitive film carried by a movable member andprovided with a longitudinally extending slot, a straight flexiblemember for continuously sealing said slot and having its respective endsflxedly connected to rotatable supports, an aperture in said flexiblemember, a carriage, a light proof container on said carriage, a lightproof rigid coupling fixed to said container and said flexible member atsaid aperture, means for driving said carriage to thereby move saidflexible member longitudinally of said slot and cause the end portionsthereof to be wound on said rotatable supports, and means for applying aforce to one of said rotatable supports to cause it to exert a pull uponthe part of said flexible member upon which a push is exerted by saidcoupling means when said carriage is moved.

HARRY PFANNENSTIEHL.

